As shown in FIG. 6, a conventional bicycle rack 50 is connected to a connection member 43 which is fixed to an extension tube 41 connected with a connection sphere 421 on a frame 42. The extension tube 41 is fixed to a rear end of the vehicle and the connection member 43 has two lugs 431 extending from an underside thereof. The extension tube 41 is located between the two lugs 431 and a bolt 432 extends through the lugs 431 and through the extension tube 41. Nevertheless, the connection member 43 tends to shake during riding of the vehicle and the shaking is transferred to the bicycle rack and the bicycles on the rack. This results a severe shear force on the bolt 432 which could be broken within a short period of time.
The present invention intends to provide a connection member that can be fixedly connected to the extension tube so as to prevent the shaking of the bicycle rack.